C++ Bresenham 3d Line Drawing Algorithm
// Bresenham3D | |
// | |
// A slightly modified version of the source found at | |
// http://www.ict.griffith.edu.au/anthony/info/graphics/bresenham.procs | |
// Provided by Anthony Thyssen, though he does not take credit for the original implementation | |
// | |
// It is highly likely that the original Author was Bob Pendelton, as referenced here | |
// | |
// ftp://ftp.isc.org/pub/usenet/comp.sources.unix/volume26/line3d | |
// | |
// line3d was dervied from DigitalLine.c published as "Digital Line Drawing" | |
// by Paul Heckbert from "Graphics Gems", Academic Press, 1990 | |
// | |
// 3D modifications by Bob Pendleton. The original source code was in the public | |
// domain, the author of the 3D version places his modifications in the | |
// public domain as well. | |
// | |
// line3d uses Bresenham's algorithm to generate the 3 dimensional points on a | |
// line from (x1, y1, z1) to (x2, y2, z2) | |
// | |
void Bresenham3D(int x1, int y1, int z1, const int x2, const int y2, const int z2, WorldMap *output, int symbol){ | |
int i, dx, dy, dz, l, m, n, x_inc, y_inc, z_inc, err_1, err_2, dx2, dy2, dz2; | |
int point[3]; | |
point[0] = x1; | |
point[1] = y1; | |
point[2] = z1; | |
dx = x2 - x1; | |
dy = y2 - y1; | |
dz = z2 - z1; | |
x_inc = (dx < 0) ? -1 : 1; | |
l = abs(dx); | |
y_inc = (dy < 0) ? -1 : 1; | |
m = abs(dy); | |
z_inc = (dz < 0) ? -1 : 1; | |
n = abs(dz); | |
dx2 = l << 1; | |
dy2 = m << 1; | |
dz2 = n << 1; | |
if ((l >= m) && (l >= n)) { | |
err_1 = dy2 - l; | |
err_2 = dz2 - l; | |
for (i = 0; i < l; i++) { | |
output->getTileAt(point[0], point[1], point[2])->setSymbol(symbol); | |
if (err_1 > 0) { | |
point[1] += y_inc; | |
err_1 -= dx2; | |
} | |
if (err_2 > 0) { | |
point[2] += z_inc; | |
err_2 -= dx2; | |
} | |
err_1 += dy2; | |
err_2 += dz2; | |
point[0] += x_inc; | |
} | |
} else if ((m >= l) && (m >= n)) { | |
err_1 = dx2 - m; | |
err_2 = dz2 - m; | |
for (i = 0; i < m; i++) { | |
output->getTileAt(point[0], point[1], point[2])->setSymbol(symbol); | |
if (err_1 > 0) { | |
point[0] += x_inc; | |
err_1 -= dy2; | |
} | |
if (err_2 > 0) { | |
point[2] += z_inc; | |
err_2 -= dy2; | |
} | |
err_1 += dx2; | |
err_2 += dz2; | |
point[1] += y_inc; | |
} | |
} else { | |
err_1 = dy2 - n; | |
err_2 = dx2 - n; | |
for (i = 0; i < n; i++) { | |
output->getTileAt(point[0], point[1], point[2])->setSymbol(symbol); | |
if (err_1 > 0) { | |
point[1] += y_inc; | |
err_1 -= dz2; | |
} | |
if (err_2 > 0) { | |
point[0] += x_inc; | |
err_2 -= dz2; | |
} | |
err_1 += dy2; | |
err_2 += dx2; | |
point[2] += z_inc; | |
} | |
} | |
output->getTileAt(point[0], point[1], point[2])->setSymbol(symbol); | |
} |
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@sriharsha48 That's what the Bresenham's line algorithm is all about; drawing a line on a grid. From Wikipedia:
It it supposed to only work with integer values... now, let's give it a try. :) |
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Seems to be working great! Many thanks @yamamushi! If anyone's interested, the screenshot is from a level editor I'm working on called Edddy. |
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@Modanung glad you found it useful! Your level editor looks awesome by the way :) |
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Hi,What if my coordinates x1.y1,z1 are of type ;double',then I am getting this : error C2296: '<<' : illegal, left operand has type 'double'
Can you please explain the way to rectify this error.
Also,if I want to use for a size of some 0.3 or 0.5,I want to fix one paramter 'resolution',Which can have any value like 0.3 or 0.5 or 1.
I think,your code only works for a grid size of 1,right?